Nowadays, various kinds of electronic appliances—such as navigation devices, music players, DVD players, television receivers ready for analog and digital broadcasts—are made compact and are offered as portable or vehicle-mountable devices.
Some of these vehicle-mounted electronic appliances, for example navigation devices, are, when used, fitted to the dashboard of a vehicle.
Today, there are even offered electronic appliances that are both vehicle-mountable and portable by being furnished with a built-in power supply or a means of connection to an AC (alternating-current) power supply so that, when removed from a vehicle, they can be carried around for use as portable appliances or at home. These vehicle-mounted electronic appliances are fairly easy to remove from the dashboard, and are therefore prone to theft (burglary).
Various proposals have been made for dealing with situations where such vehicle-mounted electronic appliances face the danger of being stolen.
For example, Patent Document 1 (JP-A-2004-355241) listed below discloses a vehicle communication ECU (electric or electronic control unit) and a method of monitoring it against theft.
The technology disclosed in Patent Document 1 is directed to a device that permits a vehicle-mounted appliance to communicate with the outside via a wireless device; a sensor is provided which monitors the fitting state of the vehicle-mounted appliance to a vehicle, and the sensor watches out for abnormal removal as in theft. Based on the monitoring output from the sensor, the wireless device notifies a control center of the theft. Simultaneously, the wireless device is locked so as to become unusable.
On the other hand, Patent Document 2 (JP-B-3565125) listed below discloses a device that warns of an accident-prone road section when there is one within a predetermined range in the direction in which the vehicle of interest is traveling.
According to the technology disclosed in Patent Document 2, road sections that were prone to accidents in the past are previously stored in the form of accident-prone road section information in which accident-prone road sections are, in a form organized one by one, represented by the latitudes and longitudes of their end points and of midway points such as crossroads; it is checked whether or not at least two of the end and midway points of an accident-prone road section are included in a predetermined range in the direction in which the vehicle of interest is traveling, and if it is judged that at least two such points are included, a warning is given of approach to the accident-prone road section.    Patent Document 1: JP-A-2004-355241 (paragraphs [0018]-[0029], and [0029]-[0037]).    Patent Document 2: JP-B-3565125 (paragraphs [0012], [0014], and [0016]-[0025]).